Effect of Different Sources of Phosphate Fertilizers on Cadmium Accumulation in Potato Tubers (Solanum tuberosum L.) in the Calcareous Soils of Iran

Potato (Solanum tuberosum L.) is the fourth most important agricultural crop after wheat, rice, and maize around the world, so increasing its quality (with a low amount of contaminants) is very important and notable. If for any reason, Cadmium (Cd) concentration increases in the soil, its uptake by the potato will be increased as a result. One of the main sources of Cd in the soil is the application of imbalanced fertilization especially consuming imported phosphate fertilizers. In order to investigate the effect of different sources of P-fertilizers on the Cd accumulation in potato tubers, an experiment was carried out on a farm in Dehgolan, Iran. This experiment was conducted based on a Randomized Complete Block Design (RCBD) with three replications. Before starting the experiment, soil and P-fertilizer samples were taken and analyzed in the laboratory. The concentration of soil available P, Zn, and Cd were 8.0, 0.75, and 0.15 mg kg-1 respectively and the concentration of Cd in different P-fertilizers were 5, 15, and 25 mg kg-1 respectively. Experimental treatments were: T1 (control) = Without P; T2 = T1+RP (Rock Phosphate); T3 = T1+SSP (Simple superphosphate) and T4 = T1+TSP (Triple superphosphate). The results revealed that Cd concentration in T1 was 0.10, in T2 was 0.13, in T3 was 0.25 and in T4 was 0.29 mg kg-1. Thus, TSP caused maximum, and RP caused the least Cd accumulation in potato tubers (p <0.01). According to the obtained results, it can be concluded that application of P-fertilizers should be based on the soil test results and using rock phosphate and simple superphosphate should become a priority, we have to select P-fertilizers which has the lowest Cd concentration, and to take care of controlling the quality of imported P-fertilizers especially their Cd content.